TW201827877A - Lens assembly - Google Patents

Abstract

A lens assembly includes a first lens, a second lens, a stop, a third lens and a fourth lens, all of which are arranged in order from an object side to an image side along an optical axis. The first lens is with negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side. The second lens is a biconvex lens with positive refractive power. The third lens is with refractive power and includes a concave surface facing the object side and a convex surface facing the image side. The fourth lens is with positive refractive power and includes a convex surface facing the image side.

Description

Imaging lens (14)

The invention relates to an imaging lens.

With the different application requirements, today's imaging lenses need to have a high-resolution capability in addition to the characteristics of a larger viewing angle. The conventional imaging lenses can no longer meet today's needs and require another new architecture for imaging The lens can satisfy the characteristics of larger viewing angle and high resolution at the same time.

In view of this, the main purpose of the present invention is to provide an imaging lens which has the characteristics of a large viewing angle and high resolution, but still has good optical performance.

The imaging lens of the present invention includes a first lens, a second lens, an aperture, a third lens, and a fourth lens in sequence from an object side to an image side along an optical axis. The first lens has negative refractive power. The first lens includes a convex surface facing the object side and a concave surface facing the image side. The second lens is a biconvex lens with positive refractive power. The third lens has refractive power. The third lens includes a concave surface facing the object side and a convex surface facing the image side. The fourth lens has a positive refractive power. The fourth lens includes a convex surface facing the image side.

The imaging lens of the present invention includes a first lens, a second lens, a third lens, and a fourth lens in sequence along an optical axis from an object side to an image side. The first lens has negative refractive power. The first lens includes a convex surface facing the object side and a concave surface facing the image side. The second lens is a biconvex lens with positive refractive power. The third lens has refractive power. The third lens includes a concave surface facing the object side and a convex surface facing the image side. The fourth lens has positive refractive power. The fourth lens includes a convex surface facing the image side. The first lens, the second lens, the third lens, and the fourth lens satisfy the following conditions: Vd ₁ 40; Vd ₂ 40; Vd ₃ 40; Vd ₄ 40; where, Vd ₁ is the Abbe coefficient of the first lens, Vd ₂ is the Abbe coefficient of the second lens, Vd ₃ is the Abbe coefficient of the third lens, and Vd ₄ is the Abbe coefficient of the fourth lens.

The third lens has positive refractive power.

The third lens has negative refractive power.

The fourth lens may further include a convex surface facing the object side.

The fourth lens may further include a concave surface facing the object side.

The first lens meets the following conditions: 0.6 R ₁₁ -R ₁₂ 0.7; 0.3 (R ₁₁ -R ₁₂ )/(R ₁₁ +R ₁₂ ) 0.4; -3.0 (R ₂₁ -R ₂₂ )/(R ₂₁ +R ₂₂ ) -2.0; -0.1 (R ₃₁ -R ₃₂ )/(R ₃₁ +R ₃₂ ) 0.1; where, R ₁₁ is the radius of curvature of the object side of the first lens, R ₁₂ is the radius of curvature of the image side of the first lens, R ₂₁ is the radius of curvature of the object side of the second lens, and R ₂₂ is the radius of curvature of the second lens The radius of curvature of the image side, R ₃₁ is the radius of curvature of the object side of the third lens, and R ₃₂ is the radius of curvature of the image side of the third lens.

The imaging lens meets the following conditions: 0.6 SL/TTL 0.8; where, SL is a distance from the aperture to an imaging plane on the optical axis, and TTL is a distance from the object side of the first lens to the imaging plane on the optical axis.

The imaging lens meets the following conditions: -0.9 f/f ₁ -0.6; -0.1 f/f ₃ 0.4; 3.0 f ₄ /f 6.0; where, f is the effective focal length of the imaging lens, f ₁ is the effective focal length of the first lens, f ₃ is the effective focal length of the third lens, and f ₄ is the effective focal length of the fourth lens.

The imaging lens satisfies the following conditions: Vd ₁ = Vd ₂ = Vd ₃ = Vd ₄ ; where Vd ₁ is the Abbe coefficient of the first lens, Vd ₂ is the Abbe coefficient of the second lens, and Vd ₃ is the third lens Abbe coefficient, Vd ₄ is the Abbe coefficient of the fourth lens.

In order to make the above objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described in detail below in conjunction with the accompanying drawings.

1, 2, 3‧‧‧ imaging lens

L11, L21, L31 ‧‧‧ first lens

L12, L22, L32 ‧‧‧ second lens

L13, L23, L33 ‧‧‧ third lens

L14, L24, L34 ‧‧‧ fourth lens

ST1, ST2, ST3 ‧‧‧ aperture

OF1, OF2, OF3 ‧‧‧ filter

CG1, CG2, CG3‧‧‧protective glass

OA1, OA2, OA3 ‧‧‧ optical axis

IMA1, IMA2, IMA3 ‧‧‧ imaging surface

S11, S12, S13, S14, S15

S16, S17, S18, S19, S110

S111, S112, S113

S21, S22, S23, S24, S25

S26, S27, S28, S29, S210

S211, S212, S213

S31, S32, S33, S34, S35

S36, S37, S38, S39, S310

S311, S312, S313

FIG. 1 is a schematic diagram of the lens configuration and optical path of the first embodiment of the imaging lens according to the present invention.

Figure 2A is a graph of the field curvature of the imaging lens of Figure 1.

Figure 2B is a distortion diagram of the imaging lens of Figure 1.

Figure 2C is a diagram of the modulation transfer function of the imaging lens of Figure 1.

FIG. 3 is a schematic diagram of the lens configuration and optical path of the second embodiment of the imaging lens according to the present invention.

Figure 4A is a field curvature diagram of the imaging lens of Figure 3.

Figure 4B is a distortion diagram of the imaging lens of Figure 3.

FIG. 4C is a modulation conversion function diagram of the imaging lens of FIG. 3.

FIG. 5 is a schematic diagram of the lens configuration and optical path of the third embodiment of the imaging lens according to the present invention.

Figure 6A is a graph of the field curvature of the imaging lens of Figure 5.

Figure 6B is a distortion diagram of the imaging lens of Figure 5.

FIG. 6C is a modulation conversion function diagram of the imaging lens of FIG. 5.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a lens configuration and an optical path according to the first embodiment of the imaging lens of the present invention. The imaging lens 1 includes a first lens L11, a second lens L12, an aperture ST1, a third lens L13, a fourth lens L14, and a filter in order from an object side to an image side along an optical axis OA1 Optical sheet OF1 and a protective glass CG1. When imaging, the light from the object side is finally imaged on an imaging surface IMA1.

The first lens L11 is a convex-concave lens with negative refractive power and is made of plastic material. The object side S11 is convex, the image side S12 is concave, and both the object side S11 and the image side S12 are aspherical surfaces.

The second lens L12 is a biconvex lens with positive refractive power made of plastic material. Its object side S13 is convex, the image side S14 is convex, and both the object side S13 and the image side S14 are aspherical surfaces.

The third lens L13 is a concave-convex lens which has a positive refractive power and is made of plastic material. Its object side S16 is concave, the image side S17 is convex, and both the object side S16 and the image side S17 are aspherical surfaces.

The fourth lens L14 is a biconvex lens with positive refractive power made of plastic material. The object side S18 is convex, the image side S19 is convex, and both the object side S18 and the image side S19 are aspherical surfaces.

The object side S110 and the image side S111 of the filter OF1 are both flat.

The object side S112 and the image side S113 of the protective glass CG1 are both flat.

In addition, the imaging lens 1 in the first embodiment satisfies any one of the following thirteen conditions:

Vd1 ₁ =Vd1 ₂ =Vd1 ₃ =Vd1 ₄ (13)

Where, Vd1 ₁ is the Abbe coefficient of the first lens L11, Vd1 ₂ is the Abbe coefficient of the second lens L12, Vd1 ₃ is the Abbe coefficient of the third lens L13, and Vd1 ₄ is the Abbe coefficient of the fourth lens L14, R1 ₁₁ is the radius of curvature of the object side S11 of the first lens L11, R1 ₁₂ is the radius of curvature of the image side S12 of the first lens L11, R1 ₂₁ is the radius of curvature of the object side S13 of the second lens L12, and R1 ₂₂ is the second The radius of curvature of the image side S14 of the lens L12, R1 ₃₁ is the radius of curvature of the object side S16 of the third lens L13, R1 ₃₂ is the radius of curvature of the image side S17 of the third lens L13, SL1 is the aperture ST1 to the imaging plane IMA1 The distance between the axes OA1, TTL1 is the distance from the object side S11 of the first lens L11 to the imaging plane IMA1 on the optical axis OA1, f1 is the effective focal length of the imaging lens 1, f1 ₁ is the effective focal length of the first lens L11, f1 ₃ Is the effective focal length of the third lens L13, and f1 ₄ is the effective focal length of the fourth lens L14.

With the above lens, aperture and the design satisfying the conditions (1) to (13), the imaging lens 1 can improve the angle of view, improve the resolution, and effectively correct aberrations.

Table 1 is a table of related parameters of each lens of the imaging lens 1 in FIG. 1. The data in Table 1 shows that the effective focal length of the imaging lens 1 of the first embodiment is 1.921 mm, the aperture value is 2.4, and the total lens length is 5.181 mm. The angle of view is equal to 100 degrees.

The aspherical surface concave degree z of each lens in Table 1 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴ +Gh ¹⁶

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~G: aspherical coefficient.

Table 2 is the related parameter table of the aspherical surface of each lens in Table 1, where k is the conic constant and A~G are the aspherical coefficients.

In the imaging lens 1 of the first embodiment, the Abbe coefficient Vd1 _{1 of} the first lens L11 =20.370, the Abbe coefficient Vd1 _{2 of the} second lens L12 =20.370, and the Abbe coefficient Vd1 _{3 of the} third lens L13 =20.370, The Abbe coefficient Vd1 _{4 of the} four lenses L14 = 20.370, the radius of curvature R1 ₁₁ of the object side S11 of the first lens L11 = 1.329 mm, the radius of curvature R1 ₁₂ of the image side S12 of the first lens L11 = 0.683 mm, and the second lens L12 The radius of curvature R1 ₂₁ of the object side S13 = 1.263 mm, the radius of curvature R1 ₂₂ of the image side S14 of the second lens L12 ₂₂ = -3.72 mm, the radius of curvature R1 ₃₁ of the object side S16 of the third lens L13 = -0.828 mm, The radius of curvature R1 ₃₂ of the image side S17 of the three lens L13 = -0.883 mm, the distance SL1 = 3.365 mm from the aperture ST1 to the imaging plane IMA1 on the optical axis OA1, and the object side S11 of the first lens L11 to the imaging plane IMA1 is on the optical axis the pitch OA1 TTL1 = 5.181mm, the effective focal length of the imaging lens 1 f1 = 1.921mm, the effective focal length of the first lens L11 f1 ₁ = -2.652mm, the effective focal length of the third lens L13 f1 ₃ = 27.019mm, the fourth lens The effective focal length of L14 f1 ₄ = 8.09mm. Vd1 ₁ can be obtained from the above information 40, Vd1 ₂ 40, Vd1 ₃ 40, Vd1 ₄ 40, R1 ₁₁ -R1 ₁₂ =0.646, (R1 ₁₁ -R1 ₁₂ )/(R1 ₁₁ +R1 ₁₂ )=0.321, (R1 ₂₁ -R1 ₂₂ )/(R1 ₂₁ +R1 ₂₂ )=-2.028, (R1 ₃₁ -R1 ₃₂ )/(R1 ₃₁ +R1 ₃₂ )=-0.032, SL1/TTL1=0.650, f1/f1 ₁ =-0.724, f1/f1 ₃ =0.071, f1 ₄ /f1=4.211, Vd1 ₁ =Vd1 ₂ = Vd1 ₃ =Vd1 ₄ =20.370, which can meet the requirements of the above conditions (1) to (13).

In addition, the optical performance of the imaging lens 1 of the first embodiment can also meet the requirements, which can be seen from FIGS. 2A to 2C. Shown in FIG. 2A is a field curvature diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2B is a distortion diagram of the imaging lens 1 of the first embodiment. Shown in FIG. 2C is a modulation transfer function (Modulation Transfer Function) diagram of the imaging lens 1 of the first embodiment.

As can be seen from FIG. 2A, the imaging lens 1 of the first embodiment has a field curvature between -0.16mm and 0.13mm for the light with a wavelength of 0.850μm in the tangential direction and sagittal direction .

It can be seen from FIG. 2B that the distortion of the imaging lens 1 of the first embodiment to light with a wavelength of 0.850 μm is between -1.3% and 0%.

It can be seen from FIG. 2C that the imaging lens 1 of the first embodiment has a wavelength of 0.850 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the field of view heights are 0.0000 mm, 0.6900 mm, 1.3800mm, 2.0700mm, 2.3000mm, the spatial frequency is between 0lp/mm and 166lp/mm, and its modulation transfer function value is between 0.08 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 1 of the first embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 3, which is a schematic diagram of a lens configuration and an optical path according to the second embodiment of the imaging lens of the present invention. The imaging lens 2 includes a first lens L21, a second lens L22, an aperture ST2, a third lens L23, a fourth lens L24, and a filter in order from an object side to an image side along an optical axis OA2 Optical sheet OF2 and a protective glass CG2. When imaging, the light from the object side is finally imaged on an imaging surface IMA2.

The first lens L21 is a convex-concave lens with a negative refractive power made of plastic material, its object side S21 is convex, the image side S22 is concave, and both the object side S21 and the image side S22 are aspherical surfaces.

The second lens L22 is a biconvex lens made of a plastic material with positive refractive power. The object side S23 is convex, the image side S24 is convex, and both the object side S23 and the image side S24 are aspherical surfaces.

The third lens L23 is a concave-convex lens which has a positive refractive power and is made of plastic material. Its object side S26 is concave, the image side S27 is convex, and both the object side S26 and the image side S27 are aspherical surfaces.

The fourth lens L24 is a concave-convex lens which has positive refractive power and is made of plastic material. Its object side S28 is concave, the image side S29 is convex, and both the object side S28 and the image side S29 are aspherical surfaces.

The object side S210 and the image side S211 of the filter OF2 are both flat.

The object side S212 and the image side S213 of the protective glass CG2 are both flat.

In addition, the imaging lens 2 in the second embodiment satisfies any one of the following thirteen conditions:

Vd2 ₁ =Vd2 ₂ =Vd2 ₃ =Vd2 ₄ (26)

Among them, Vd2 ₁ is the Abbe coefficient of the first lens L21, Vd2 ₂ is the Abbe coefficient of the second lens L22, Vd2 ₃ is the Abbe coefficient of the third lens L23, and Vd2 ₄ is the Abbe coefficient of the fourth lens L24, R2 ₁₁ is the radius of curvature of the object side S21 of the first lens L21, R2 ₁₂ is the radius of curvature of the image side S22 of the first lens L21, R2 ₂₁ is the radius of curvature of the object side S23 of the second lens L22, and R2 ₂₂ is the second The radius of curvature of the image side S24 of the lens L22, R2 ₃₁ is the radius of curvature of the object side S26 of the third lens L23, R2 ₃₂ is the radius of curvature of the image side S27 of the third lens L23, SL2 is the aperture ST2 to the imaging plane IMA2 The distance between the axes OA2, TTL2 is the distance from the object side S21 of the first lens L21 to the imaging plane IMA2 on the optical axis OA2, f2 is the effective focal length of the imaging lens 2, f2 ₁ is the effective focal length of the first lens L21, f2 ₃ an effective focal length of the third lens L23, f2 ₄ as the effective focal length of the fourth lens L24.

With the above lens, aperture and the design satisfying the conditions (14) to (26), the imaging lens 2 can improve the angle of view, improve the resolution, and effectively correct the aberration.

Table 3 is a table of related parameters of each lens of the imaging lens 2 in FIG. 3. The data in Table 3 shows that the effective focal length of the imaging lens 2 of the second embodiment is 1.971 mm, the aperture value is 2.0, and the total lens length is 4.978 mm. The angle of view is equal to 90 degrees.

The aspherical surface depression degree z of each lens in Table 3 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴ +Gh ¹⁶

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~G: aspherical coefficient.

Table 4 is the related parameter table of the aspherical surface of each lens in Table 3, where k is the conic constant and A~G are the aspherical coefficients.

In the imaging lens 2 of the second embodiment, the Abbe coefficient Vd2 _{1 of} the first lens L21 =20.370, the Abbe coefficient Vd2 _{2 of the} second lens L22 =20.370, and the Abbe coefficient Vd2 _{3 of the} third lens L23 =20.370, The Abbe coefficient Vd2 _{4 of the} four lenses L24 ₄ = 20.370, the radius of curvature R2 ₁₁ of the object side S21 of the first lens L21 ₁₁ = 1.249 mm, the radius of curvature R2 ₁₂ of the image side S22 of the first lens L21 ₁₂ = 0.625 mm, and the second lens L22 The radius of curvature R2 ₂₁ of the object side S23 = 1.471 mm, the radius of curvature R2 ₂₂ of the image side S24 of the second lens L22 ₂₂ = -3.384 mm, and the radius of curvature R2 ₃₁ of the object side S26 of the third lens L23 ₃₁ = -1.393 mm, The radius of curvature R2 of the image side S27 of the three lens L23 ₃₂ = -1.14 mm, the distance SL2 = 3.625 mm from the aperture ST2 to the imaging plane IMA2 on the optical axis OA2, and the object side S21 of the first lens L21 to the imaging plane IMA2 is on the optical axis the pitch OA2 TTL2 = 4.978mm, the effective focal length of the imaging lens 2 of f2 = 1.971mm, the effective focal length of the first lens L21 f2 ₁ = -2.38mm, the effective focal length of the third lens L23 f2 ₃ = 5.231mm, the fourth lens The effective focal length of L24 f2 ₄ =7.573mm. Vd2 ₁ can be obtained from the above information 40, Vd2 ₂ 40, Vd2 ₃ 40, Vd2 ₄ 40, R2 ₁₁ -R2 ₁₂ =0.624, (R2 ₁₁ -R2 ₁₂ )/(R2 ₁₁ +R2 ₁₂ )=0.333, (R2 ₂₁ -R2 ₂₂ )/(R2 ₂₁ +R2 ₂₂ )=-2.583, (R2 ₃₁ -R2 ₃₂ )/(R2 ₃₁ +R2 ₃₂ )=0.100, SL2/TTL2=0.728, f2/f2 ₁ =-0.828, f2/f2 ₃ =0.377, f2 ₄ /f2=3.842, Vd2 ₁ =Vd2 ₂ =Vd2 ₃ =Vd2 ₄ =20.370, all can meet the requirements of the above conditions (14) to (26).

In addition, the optical performance of the imaging lens 2 of the second embodiment can also meet the requirements, which can be seen from FIGS. 4A to 4C. FIG. 4A is a field curvature diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4B is a distortion diagram of the imaging lens 2 of the second embodiment. Shown in FIG. 4C is a modulation transfer function diagram of the imaging lens 2 of the second embodiment.

As can be seen from FIG. 4A, the imaging lens 2 of the first embodiment has a field curvature between -0.06mm and 0.10mm for the light with a wavelength of 0.850μm in the tangential and sagittal directions .

It can be seen from FIG. 4B that the distortion of the imaging lens 2 of the second embodiment to light with a wavelength of 0.850 μm is between -2.4% and 0%.

It can be seen from FIG. 4C that the imaging lens 2 of the second embodiment pairs of rays with a wavelength of 0.850 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the angles of view are 0.00 degrees, 10.00 degrees, 20.00 degrees, 25.00 degrees, 35.00 degrees, 45.00 degrees, the spatial frequency is between 0lp/mm to 166lp/mm, and its modulation transfer function value is between 0.22 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 2 of the second embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 5. FIG. 5 is a schematic diagram of a lens configuration and an optical path of a third embodiment of the imaging lens according to the present invention. The imaging lens 3 includes a first lens L31, a second lens L32, an aperture ST3, a third lens L33, a fourth lens L34, and a filter in order from an object side to an image side along an optical axis OA3 Optical sheet OF3 and a protective glass CG3. When imaging, the light from the object side is finally imaged on an imaging surface IMA3.

The first lens L31 is a convex-concave lens with negative refractive power and is made of plastic material. Its object side S31 is convex, the image side S32 is concave, and both the object side S31 and the image side S32 are aspherical surfaces.

The second lens L32 is a biconvex lens with a positive refractive power made of plastic material, its object side S33 is convex, the image side S34 is convex, and both the object side S33 and the image side S34 are aspherical surfaces.

The third lens L33 is a convex-concave lens with negative refractive power made of plastic material. Its object side S36 is concave, the image side S37 is convex, and both the object side S36 and the image side S37 are aspherical surfaces.

The fourth lens L34 is a biconvex lens with positive refractive power made of plastic material, its object side S38 is convex, the image side S39 is convex, and both the object side S38 and the image side S39 are aspherical surfaces.

The object side S310 and the image side S311 of the filter OF3 are both flat.

The object side S312 and the image side S313 of the protective glass CG3 are both flat.

In addition, the imaging lens 3 in the third embodiment satisfies any one of the following twelve conditions:

Where Vd3 ₁ is the Abbe coefficient of the first lens L31, Vd3 ₂ is the Abbe coefficient of the second lens L32, Vd3 ₃ is the Abbe coefficient of the third lens L33, and Vd3 ₄ is the Abbe coefficient of the fourth lens L34, R3 ₁₁ is the radius of curvature of the object side S31 of the first lens L31, R3 ₁₂ is the radius of curvature of the image side S32 of the first lens L31, R3 ₂₁ is the radius of curvature of the object side S33 of the second lens L32, and R3 ₂₂ is the second The radius of curvature of the image side S34 of the lens L32, R3 ₃₁ is the radius of curvature of the object side S36 of the third lens L33, R3 ₃₂ is the radius of curvature of the image side S37 of the third lens L33, SL3 is the aperture ST3 to the imaging plane IMA3 The distance between the axes OA3, TTL3 is the distance from the object side S31 of the first lens L31 to the imaging plane IMA3 on the optical axis OA3, f3 is the effective focal length of the imaging lens 3, f3 ₁ is the effective focal length of the first lens L31, f3 ₃ Is the effective focal length of the third lens L33, and f3 ₄ is the effective focal length of the fourth lens L34.

With the above lens, aperture, and design that satisfies the conditions (27) to (38), the imaging lens 3 can improve the angle of view, improve the resolution, and effectively correct aberrations.

Table 5 is a table of related parameters of each lens of the imaging lens 3 in FIG. 5. The data in Table 5 shows that the effective focal length of the imaging lens 3 of the third embodiment is 1.954 mm, the aperture value is 2.0, and the total lens length is 4.931 mm. The angle of view is equal to 100 degrees.

The aspherical surface depression degree z of each lens in Table 5 is obtained by the following formula: z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴ +Gh ¹⁶

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~G: aspherical coefficient.

Table 6 is the related parameter table of the aspherical surface of each lens in Table 5, where k is the conic constant and A~G are the aspherical coefficients.

The imaging lens 3 of the third embodiment, a first Abbe's number of the lens L31 Vd3 ₁ = 20.370, Abbe's number of the second lens L32 Vd3 ₂ = 20.370, Abbe's number of the third lens L33 Vd3 ₃ = 22, the first The Abbe coefficient Vd3 _{4 of the} four lens L34 ₄ = 24, the radius of curvature R3 ₁₁ of the object side S31 of the first lens L31 ₁₁ = 1.334 mm, the radius of curvature R3 ₁₂ of the image side S32 of the first lens L31 =0.709 mm, the second lens L32 The radius of curvature R3 ₂₁ of the object side S33 ₂₁ =1.213 mm, the radius of curvature R3 ₂₂ of the image side S34 of the second lens L32 ₂₂ =-3.406 mm, and the radius of curvature R3 ₃₁ of the object side S36 of the third lens L33 ₃₁ =-0.801 mm, The radius of curvature R3 ₃₂ of the image side S37 of the three lens L33 = -0.913 mm, the distance SL3 = 3.094 mm from the aperture ST3 to the imaging plane IMA3 on the optical axis OA3, and the object side S31 of the first lens L31 to the imaging plane IMA3 is on the optical axis The distance between OA3 and TTL3=4.931mm, the effective focal length of imaging lens 3 f3=1.954mm, the effective focal length of first lens L31 f3 ₁ =-2.885mm, the effective focal length of third lens L33 f3 ₃ =-70.946mm, the fourth The effective focal length of lens L34 f3 ₄ = 10.178 mm. Vd3 ₁ can be obtained from the above information 40, Vd3 ₂ 40, Vd3 ₃ 40, Vd3 ₄ 40, R3 ₁₁ -R3 ₁₂ =0.625, (R3 ₁₁ -R3 ₁₂ )/(R3 ₁₁ +R3 ₁₂ )=0.306, (R3 ₂₁ -R3 ₂₂ )/(R3 ₂₁ +R3 ₂₂ )=-2.106, (R3 ₃₁ -R3 ₃₂ )/(R3 ₃₁ +R3 ₃₂ )=-0.065, SL3/TTL3=0.627, f3/f3 ₁ =-0.677, f3/f3 ₃ =-0.028, f3 ₄ /f3=5.209, all can meet the above conditions (27) to the requirements of condition (38).

In addition, the optical performance of the imaging lens 3 of the third embodiment can also meet the requirements, which can be seen from FIGS. 6A to 6C. FIG. 6A is a field curvature diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6B is a distortion diagram of the imaging lens 3 of the third embodiment. Shown in FIG. 6C is a modulation transfer function (Modulation Transfer Function) diagram of the imaging lens 3 of the third embodiment.

As can be seen from FIG. 6A, the imaging lens 3 of the third embodiment has a field curvature between -0.14mm and 0.08mm for the light with a wavelength of 0.850μm in the tangential and sagittal directions .

It can be seen from FIG. 6B that the distortion of the imaging lens 3 of the third embodiment to light with a wavelength of 0.850 μm is between -2.1% and 1.1%.

As can be seen from FIG. 6C, the imaging lens 3 of the third embodiment pairs the light with a wavelength of 0.850 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the angles of view are 0.00 degrees, 10.00 degrees, 20.00 degrees, 25.00 degrees, 35.00 degrees, 50.00 degrees, the spatial frequency is between 0lp/mm and 166lp/mm, and its modulation transfer function value is between 0.12 and 1.0.

It is obvious that the field curvature and distortion of the imaging lens 3 of the third embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

Claims (11)

An imaging lens, in order from an object side to an image side along an optical axis, includes: a first lens having negative refractive power, the first lens includes a convex surface facing the object side and a concave surface facing the image side; a first Two lenses, the second lens is a biconvex lens with positive refractive power; an aperture; a third lens has refractive power, the third lens includes a concave surface facing the object side and a convex surface facing the image side; and a fourth lens has positive power Refractive power, the fourth lens includes a convex surface facing the image side. An imaging lens, in order from an object side to an image side along an optical axis, includes: a first lens having negative refractive power, the first lens includes a convex surface facing the object side and a concave surface facing the image side; a first Two lenses, the second lens is a biconvex lens with positive refractive power; a third lens has refractive power, the third lens includes a concave surface facing the object side and a convex surface facing the image side; and a fourth lens has positive refractive power, the The fourth lens includes a convex surface facing the image side; the first lens and the fourth lens satisfy the following conditions: ; Where Vd _{1 is} the Abbe coefficient of the first lens and Vd _{4 is} the Abbe coefficient of the fourth lens. The imaging lens as described in item 1 or 2 of the patent application range, wherein the third lens has a positive refractive power and the fourth lens further includes a concave surface facing the object side. The imaging lens as described in item 1 or 2 of the patent application scope, wherein the third lens has negative refractive power and the fourth lens further includes a convex surface facing the object side. The imaging lens as described in item 1 or item 2 of the patent application scope, wherein the first lens satisfies the following conditions: 0.6 R ₁₁ -R ₁₂ 0.7; where, R _{11 is} the radius of curvature of the object side of the first lens, and R _{12 is} the radius of curvature of the image side of the first lens. The imaging lens as described in item 5 of the patent application scope, wherein the first lens satisfies the following conditions: 0.3 (R ₁₁ -R ₁₂ )/(R ₁₁ +R ₁₂ ) 0.4; -3.0 (R ₂₁ -R ₂₂ )/(R ₂₁ +R ₂₂ ) -2.0; -0.1 (R ₃₁ -R ₃₂ )/(R ₃₁ +R ₃₂ ) 0.1; where, R _{11 is} the radius of curvature of the object side of the first lens, R _{12 is} the radius of curvature of the image side of the first lens, R _{21 is} the radius of curvature of the object side of the second lens, and R _{22 is} the The radius of curvature of the image side of the second lens, R _{31 is} the radius of curvature of the object side of the third lens, and R _{32 is} the radius of curvature of the image side of the third lens. The imaging lens as described in item 1 or item 2 of the patent application scope, wherein the imaging lens satisfies the following conditions: 0.6 SL/TTL 0.8; wherein, SL is a distance from the aperture to an imaging plane on the optical axis, and TTL is a distance from the object side of the first lens to the imaging plane on the optical axis. The imaging lens as described in item 1 or item 2 of the patent application scope, wherein the imaging lens satisfies the following conditions: -0.9 f/f ₁ -0.6; -0.1 f/f ₃ 0.4; 3.0 f ₄ /f 6.0; where, f is the effective focal length of the imaging lens, f _{1 is} the effective focal length of the first lens, f _{3 is} the effective focal length of the third lens, and f _{4 is} the effective focal length of the fourth lens. The imaging lens described in item 2 of the patent application scope, wherein the imaging lens satisfies the following conditions: | Vd ₂ - Vd ₄ | 25; wherein, Vd _{2 is} the Abbe coefficient of the second lens, and Vd _{4 is} the Abbe coefficient of the fourth lens. The imaging lens as described in item 9 of the patent application scope, wherein the imaging lens satisfies the following conditions: Vd ₁ 40; Vd ₂ 40; Vd ₃ 40; Vd ₄ 40; Vd ₁ = Vd ₂ = Vd ₃ = Vd ₄ ; where Vd _{1 is} the Abbe coefficient of the first lens, Vd _{2 is} the Abbe coefficient of the second lens, and Vd _{3 is} the Abbe of the third lens Coefficient, Vd _{4 is} the Abbe coefficient of the fourth lens. An imaging lens, along an optical axis, from an object side to an image side in sequence includes: a first lens having negative refractive power; a second lens having positive refractive power; a third lens having refractive power; and a fourth lens having Positive refractive power; the first lens, the second lens, the third lens, and the fourth lens satisfy the following conditions: | Vd ₂ - Vd ₄ | 25; 0.6 SL/TTL 0.8; -0.9 f/f ₁ -0.6; -0.1 f/f ₃ 0.4; 3.0 f ₄ /f 6.0; 0.6 R ₁₁ -R ₁₂ 0.7; -3.0 (R ₂₁ -R ₂₂ )/(R ₂₁ +R ₂₂ ) -2.0; -0.1 (R ₃₁ -R ₃₂ )/(R ₃₁ +R ₃₂ ) 0.1; where, Vd _{1 is} the Abbe coefficient of the first lens, Vd _{2 is} the Abbe coefficient of the second lens, Vd _{4 is} the Abbe coefficient of the fourth lens, and SL is the aperture to an imaging plane at the A pitch on the optical axis, TTL is a pitch on the optical axis from the object side of the first lens to the imaging plane, f is the effective focal length of the imaging lens, f _{1 is} the effective focal length of the first lens, f _{3 is} the effective focal length of the third lens, f _{4 is} the effective focal length of the fourth lens, R _{11 is} the radius of curvature of the object side of the first lens, R _{12 is} the radius of curvature of the image side of the first lens, R _{21 is} the radius of curvature of the object side of the second lens, R _{22 is} the radius of curvature of the image side of the second lens, R _{31 is} the radius of curvature of the object side of the third lens, and R _{32 is} the image of the third lens Radius of curvature on the side.